This invention relates to novel imidazoles and more particularly to novel 1-substituted-5-nitro-2-(2-dialkylaminovinyl)-imidazoles, as well as to a process for preparing these and other imidazoles.
Nitroimidazole derivatives having useful antimicrobial properties are known in the art and have been described, for example, in German unexamined published application Nos. 1,920,150 and 1,935,685.
Several compounds of Formula II set forth hereinbelow have already been obtained by various different processes. Thus, published Dutch Patent application No. 64 13814 describes the reaction of 1-substituted 5-nitroimidazoles with paraformaldehyde in dimethyl sulfoxide in an autoclave at 110.degree. C. over a period of 24 hours to obtain the corresponding 2-hydroxymethyl derivatives, and German unexamined published application No. 1,595,928 discloses the oxidation of the 2-hydroxymethyl compound of Formula II to the corresponding 2-formyl compound.
Due to the drastic reaction conditions, particularly the prolonged reaction times at high temperatures and elevated pressures, this process is complicated to perform, particularly on a large scale, and gives a poor yield.
Another conventional process for the production of the 1-formyl derivatives is likewise disadvantageous, especially because of the rather large number of reaction stages. For example, according to the procedure described in U.S. Pat. No. 3,549,626, benzaldehyde is reacted with 5-nitro-1,2-dimethylimidazole, water is next split off with sulfuric acid, and the aldehyde is subsequently obtained by oxidation and then immediately reacted to the thiosemicarbazone.
Both of these conventional prior art processes exhibit the additional disadvantage that the substituent at the 1-position of the imidazole ring can represent only those groups withstanding the harsh reaction conditions, e.g., alkyl and benzyloxyalkyl.